Organisms and Populations

Which one of the following population interactions is widely used in medical science for the production of antibiotics?

1. Commensalism
2. Mutualism
3. Parasitism
4. Amensalism

Natality refers to

1. death rate
2. birth rate
3. number of individuals leaving the habitat
4. number of individuals entering a habitat

In a growing population of a country,

1. pre-reproductive individuals are more than the reproductive individuals
2. reproductive individuals are less than the post-reproductive individuals
3. reproductive and pre-reproductive individuals are equal in number
4. pre-reproductive individuals are less than the reproductive individuals.

Asymptote in a logistic growth curve is obtained when :

1. K > N
2. The value of 'r' approaches zero
3. K < N
4. K = N

Plants which produce characteristic pneumatophores and show vivipary belong to :

1. Halophytes
2. Psammophytes
3. Hydrophytes
4. Mesophytes

Mycorrhizae are the example of :

1. Fungistasis
2. Antibiosis
3. Mutualism
4. Amensalism

It is much easier for a small animal to run uphill than for a large animal, because -

1. The efficiency of muscles in large animals is less than in the small animals
2. Smaller animals have a higher metabolic rate
3. It is easier to carry a small body weight
4. Small animals have a lower O2 requirement

When does the growth rate of a population following the logistic model equal zero? The logistic model is given as dN/dt = rN(1-N/K)

1. When death rate is greater than birth rate.
2. When N/K equals zero.
3. When N/K is exactly one.
4. When N nears the carrying capacity of the habitat.

Gause's principle of competitive exclusion states that -

1. Larger organisms exclude smaller ones through competition
2. More abundant species will exclude the less abundant species through competition
3. Competition for the same resources excludes species having different food preferences
4. No two species can occupy the same niche indefinitely for the same limiting resources

Which of the following is correct for r-selected species ?

1. Small number of progeny with small size
2. Small number of progeny with large size
3. Large number of progeny with small size
4. Large number of progeny with large size